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mfleming · 01-13-2018, 02:19 AM

(01-13-2018 12:37 AM)rprosperi Wrote: Thanks for sharing your results Mark.

Did you cut both sides, or only the contact that touches the positive 'button' terminal. I presume both, but the photo could imply just one (or more likely was used to show the difference before/after trim)? Just wanted to make sure, as my parts are on their way.

I cut only the side with the button top in contact with the spring. That spring was nearly compressed fully, but now has about as much coil slack as the other side. The ease with which the case can be removed or inserted is very noticeable (I was pressing harder than what I felt comfortable with before surgery.)

Highly recommended!
~Mark

larthurl · 01-16-2018, 06:49 PM

(01-09-2018 04:04 PM)rprosperi Wrote:
(01-09-2018 03:48 PM)mfleming Wrote: I'm using normal buttontop Eneloop cells and the replacement springs for the 41 battery case found on TAS. The battery holder snaps into the cavity with a nice fit and spring pressure keeps the batteries pressed tightly against the contacts inside. The holder requires a firm push downward to remove, so there's very little chance the holder will pop out of the calculator. The TAS springs use a thicker wire than the stock 41 springs and are almost fully compressed when the batteries are inserted.

Excellent, thanks for these details Mark. Gonna go get me one (well, 2).

Do you have a link or item # for the springs on TAS (or elsewhere)? I've done a few searches, and besides finding plenty of 41 battery cases (ranging up to $75+ !) I don't see a listing for just the springs. I'll search old posts as well; IIRC, Sylvain found some somewhere a couple years ago.

Update - Found it:

https://www.ebay.com/itm/6x-Copper-Spring-Coil-and-6x-Contact-For-Dual-18650-Lithium-Batteries/253193465702

Does this look like it will work (often the strand that connects across the bottom is diagonal, this one is straight)?

Hey Bob:

Thanks for the link and info on the springs and contact pieces.
I was trying to get my 32E working (the battery was dead and charger wouldn't make it work.
SO I used a pair of Eneloops, and the contact piece I received in my order.
Boy, that's a tight fit. If I rotate/jiggle the batteries, I can get the display to work correctly.
If not, I only get sixes lit up in the display (top right segment in all LED numbers won't light.)

I need to monkey with it some more because there really isn't room fro the Eneloops and that connector piece.

At least I'll be ready for seeing if my father's woodstock will work when the 3-D printed battery holder arrives.

.....Art

larthurl · 01-16-2018, 06:55 PM

(01-13-2018 12:20 AM)mfleming Wrote:
(01-10-2018 06:33 PM)larthurl Wrote: Let us know how the clipping goes.
I ordered the springs too, and am curious what tool needed to cut the springs to size.

.....ARt

Here's the result of clipping two full turns from the spring, as shown in the left-hand side picture and the amount of spring compression with batteries installed on the right-hand side picture. The spring was cut with heavy duty wire cutters, and note how the end of the right-hand spring was bent inwards to make contact with the battery button.

I'll have to say this was a useful modification. The battery case is much easier to snap in and out, but the spring tension is still enough to maintain good physical and electrical contact between battery and spring. That likely puts less stress on the calculator battery contacts as well.

~Mark

Thanks for sharing the ideas Mark.
I have the batteries - Eneloops
I have the springs
I have the calculator
Just waiting eagerly for the 3-D printer battery holder.

.....Art

**rprosperi** · 01-16-2018, 09:12 PM

(01-16-2018 06:49 PM)larthurl Wrote: Hey Bob:

Thanks for the link and info on the springs and contact pieces.
I was trying to get my 32E working (the battery was dead and charger wouldn't make it work.
SO I used a pair of Eneloops, and the contact piece I received in my order.
Boy, that's a tight fit. If I rotate/jiggle the batteries, I can get the display to work correctly.
If not, I only get sixes lit up in the display (top right segment in all LED numbers won't light.)

I need to monkey with it some more because there really isn't room fro the Eneloops and that connector piece.

At least I'll be ready for seeing if my father's woodstock will work when the 3-D printed battery holder arrives.

Art,

I'm a bit confused... this thread is primarily about Woodstocks (the battery case Mark made, the springs, etc.) but you're discussing a 32E (a Spice) - the battery mounting issues are not the same.

In a Spice, batteries with the button-top are usually too tight to fit and you can easily break or damage the fragile battery tabs. Be VERY careful using these batteries as the battery bay was designed for 'flat top' cells as found in the original Spice battery holder. DO NOT USE the battery contacts that came with the springs as they are too "tall" and will likely over-stress the spring contacts in the left side (seen from back) of the 32E battery bay. Use some flat sheet metal for that contact; you can even jury-rig a contact by folding some aluminum foil several times into a 3/4" long strip.

For Spice series, I would not use standard Eneloop button cells, I recommend the pre-made batteries you can find on eBay (like these), OR rebuild the original battery holder with some flat top NiCD or NiMH cells (e.g. like this) and simply wrap it with electrical tape.

larthurl · (This post was last modified: 01-17-2018 06:26 PM by larthurl.)

(01-16-2018 09:12 PM)rprosperi Wrote:
(01-16-2018 06:49 PM)larthurl Wrote: Hey Bob:

Thanks for the link and info on the springs and contact pieces.
I was trying to get my 32E working (the battery was dead and charger wouldn't make it work.
SO I used a pair of Eneloops, and the contact piece I received in my order.
Boy, that's a tight fit. If I rotate/jiggle the batteries, I can get the display to work correctly.
If not, I only get sixes lit up in the display (top right segment in all LED numbers won't light.)

I need to monkey with it some more because there really isn't room fro the Eneloops and that connector piece.

At least I'll be ready for seeing if my father's woodstock will work when the 3-D printed battery holder arrives.

Art,

I'm a bit confused... this thread is primarily about Woodstocks (the battery case Mark made, the springs, etc.) but you're discussing a 32E (a Spice) - the battery mounting issues are not the same.

In a Spice, batteries with the button-top are usually too tight to fit and you can easily break or damage the fragile battery tabs. Be VERY careful using these batteries as the battery bay was designed for 'flat top' cells as found in the original Spice battery holder. DO NOT USE the battery contacts that came with the springs as they are too "tall" and will likely over-stress the spring contacts in the left side (seen from back) of the 32E battery bay. Use some flat sheet metal for that contact; you can even jury-rig a contact by folding some aluminum foil several times into a 3/4" long strip.

For Spice series, I would not use standard Eneloop button cells, I recommend the pre-made batteries you can find on eBay (like these), OR rebuild the original battery holder with some flat top NiCD or NiMH cells (e.g. like this) and simply wrap it with electrical tape.

Thanks, Bob.
I didn't mean to hijack the thread. The battery springs and contacts were mentioned here - and I will try to use them for the woodstock I have when the battery holder arrives..

I just shared that I tried to use the contacts (not the springs) in the 32E. Without much success.
I will take your advice on the aluminum foil.
Just curious, why not use ENeloops on the Spice machines?
And I just ordered the pre-made battery pack from the bay that you linked to. I assume that is a rechargeable pack?

.....Art

**rprosperi** · 01-17-2018, 09:03 PM

(01-17-2018 06:23 PM)larthurl Wrote: Just curious, why not use ENeloops on the Spice machines?
And I just ordered the pre-made battery pack from the bay that you linked to. I assume that is a rechargeable pack?

Eneloops are fine from a battery power perspective, however I believe (though could be wrong) that Eneloops only come in button-top style, and would stress and likely damage the battery contacts with extended use (since they are longer, they stress the contacts).

Yes, the battery pack from Waterhosko (Mark is here on the Forum from time to time) is a pair of rechargeable NiMH AA cells. The originals were much lower capacity NiCDs so this pack will definitely last longer than the original pack; I believe NiMH cells self-discharge (when not being used) a bit faster than NiCDs so its a bit of a trade-off, but your likely not buying them to just have your 32E sit in the desk drawer.

Good luck and update us with your results.

**rprosperi** · 01-22-2018, 10:41 PM

I just received my 1-piece Woodstock battery holders today, also using the spring-contacts noted above. Assembled and installed in less than 30 seconds. I use flat-top NiCD cells and that small difference in overall length seems to make a difference, as these fit like an original Woodstock pack, with no need to remove coils from the spring.

Thanks for sharing this design Mark! Best of all worlds - tight/secure/reliable enough to charge in the Woodstock, yet easy enough to pop batteries out for external charge with no need to re-glue the case top back on.

Here's a couple pics:

mfleming · 01-23-2018, 01:45 AM

Now to find the perfect coloring formula to match holder to original case color!

**rprosperi** · 01-23-2018, 03:04 AM

(01-23-2018 01:45 AM)mfleming Wrote: Now to find the perfect coloring formula to match holder to original case color!

There are a lot of articles out there claiming that dyeing 3D-printed items is easy and straightforward, but I've also seen at least as many from folks claiming that it's neither of those. In this case, I suspect color-matching will be tough, since it will be trying to match plastic that has aged 30+ years, so each Woodstock is probably slightly different. But I suppose getting close to the original putty color would be a good start. Thanks again.